Nonazeotropic working fluid media for use in thermodynamic cycle applications

ABSTRACT

A nonazeotropic working fluid medium for use in a thermodynamic cycle system, comprising a mixture of compounds and characterized in that one or more vaporization loss/replenishment cycles of each less than about 15% of the total weight of the medium and cumulative up to about 50% of the total weight of the medium result in a total decrease in the coefficient of performance of said medium of no more than about 5%, or a loss in electric power generating efficiency of not more than about 3 percent.

This is a division of application Ser. No. 08/007,398, filed Jan. 21,1993, now abandoned, which is a continuation-in-part application of Ser.No. 07/854,131 filed Mar. 19, 1992, now abandoned.

TECHNICAL FIELD

The present invention relates to working fluid media for use inthermodynamic cycle systems. More particularly, it relates tononazeotropic mixtures useful, for example, in refrigeration andair-conditioning applications and having improved vaporization losscharacteristics.

BACKGROUND ART

Commercial and industrial working fluid media for thermodynamic cyclesystems are fluids which are generally either pure compounds,azeotropes, or nonazeotropes (zeotropes).

Many such mixtures are known in the art as illustrated, for example, inthe following references:

Lewis, U.S. Pat. No. 2,641,580, granted Jun. 9, 1953, for "AzeotropicRefrigerant Composition of 1,1-Difluoroethane andMonochloropentafluoroethane".

Fuderer, U.S. Pat. No. 3,203,194, granted Aug. 31, 1965, for"Compression Process for Refrigeration".

Orfeo et al., U.S. Pat. No. 4,303,536, granted Dec. 1, 1981, for"Nonazeotropic Refrigerant Composition ContainingMonochlorodifluoromethane, And Method Of Use".

Nikolsky et al., U.S. Pat. No. 4,603,002, granted Jul. 29, 1986, for"Method And Cooling Agent For Freezing And Storing Products".

Japanese Patent Kokai 52-70466, published in 1977 to Daikin Kogyo KK,for "Low Boiling Point Refrigerant Compositions".

B.C. Langley, "Refrigeration and Air Conditioning", 2d ed. 1982.

French Patent 2,130,556 (VEB Monsator Haushalt grossgeratekombinat).

French Patent 2,177,785 (VEB Monsator Haushalt grossgeratekombinat).

French Patent 2,607,144 (Institute Francaise du Petrole).

M. F. Bouzianis, "Chlorofluorocarbons And Their Alternatives"(Arthur D.Little 1988).

D. J. Bateman et al., "Refrigerant Blends for the Automotive AirConditioning Aftermarket," SAE Technical Paper Series 900216 (SAEInternational Congress and Exposition - Detroit, Mich. Feb. 26-Mar. 2,1990).

"ASHRAE Terminology of Heating, Ventilation, Air-conditioning andRefrigeration", 2nd ed. (American Society of Heating, Refrigeration, andAir-Conditioning Engineers Inc. 1991).

Nonazeotropic refrigeration media ("NARMs") in particular are attractivebecause, during the thermodynamic cycle process, they absorb more heatduring the isobaric evaporation stage, release more heat during theisobaric condensation stage, and do more work during the expansionprocess or need less work during the compression stage than do eithersingle-compound or azeotropic working fluid media under comparableexternal conditions. In other words, NARMs have a higher "coefficient ofperformance" (defined hereinbelow) in an inverse thermodynamic cycledevice, and higher work efficiency in a normal thermodynamic cycledevice.

However, known nonazeotropic working fluid media have serious drawbacksstemming from the fact that in mechanical refrigeration, airconditioning, heat pump and hot-fluid power generation systems,vaporization loss of such media is unavoidable. This results not only inchanges in the concentrations of the components of the liquid phase ofthe working fluid media, but also results in a decrease in the weight ormass of the working fluid medium. In turn, there is a continuousdecrease in the Coefficient of Performance ("COP") and a decrease in thepower generating efficiency of hot-fluid power generation systems. (Theterm "COP" as used herein is the ratio of the rate of net energy removalfrom the environment (in the case of a refrigerant) or net energy output(in the case of a heating or power generating system) to the totalenergy input expressed in consistent units and rating conditions).Because of this, it is necessary to replenish the working fluid to itsoriginal weight level.

But with conventional NARMs, the replenished working fluid medium has adifferent composition than the original working medium aftervaporization losses. This result stems from changes in the systemconcentration, which are attributable to recharging with originalnonazeotropic medium, which mixes with a partially depleted liquidworking fluid whose composition had changed due to zeotropicvaporization. Such mixing, therefore, leads to a different concentrationof the final working fluid medium than the original working medium, andresults in a continuing decrease in the COP and a decrease in powergenerating efficiency.

Consequently, the changes in proportions (concentrations) of thecomponents of the working fluid medium make its useful life much shorterthan if its composition had remained unchanged. Inevitably the entireworking fluid medium has to be discharged and replaced. Becauseconventional NARMs have ozone depletion potential ("ODP"), and aretoxic, especially when discharged in such large quantities, thecontinued use of conventional NARMs is having and will continue to havedeleterious effects on the ozone layer and the environment. To avoidsuch problems and drawbacks requires large investments in recyclingsystems or the discovery of new ways of handling conventional NARMs thathave to be discharged in this way. Neither approach is entirelysatisfactory from a technical, economic or environmental standpoint.

Therefore, a need definitely exists for nonazeotropic working fluidmedia useful in thermodynamic cycle systems and having extended usefulworking life, with little decrease in COP and little decrease in powergenerating efficiency during repeated vaporization loss andreplenishment cycle processes.

Accordingly, it is an object of the present invention to providenonazeotropic fluid working media for use in thermodynamic compressioncycle systems, which media are improved with respect toanti-vaporization loss properties with respect to the effect on COP ofchanges in the composition of the medium resulting from repeatedvaporization loss and replenishment cycles.

Another object is to provide refrigeration, air conditioning, heatingand power generation systems using hot fluid and the like devicesemploying the aforesaid improved, nonazeotropic working fluid media.

Another object is to provide a thermodynamic engineering device operatedas a thermodynamic cycle system employing a nonazeotropic working fluidmedium having improved vaporization loss stability.

Another object is to provide an air conditioning device operated as athermodynamic cycle system employing a nonazeotropic working fluidmedium having improved vaporization loss stability.

Another object is to provide a heating device operated as athermodynamic cycle system employing a nonazeotropic working fluidmedium having improved vaporization loss stability.

Yet another object is to provide a method of transferring heat by meansof a thermodynamic compression cycle utilizing the aforesaid improvednon-azeotropic working media of the present invention.

These and other objects of the invention can be understood and achievedby reference to the following disclosure, drawings and claims.

SUMMARY OF THE INVENTION

The above objects are achieved according to the present invention by anonazeotropic working fluid medium for a thermodynamic cycle system,comprising a mixture of compounds capable of undergoing one or morevaporization loss-replenishment cycles wherein: a) after-any singlecycle, the change in weight of the medium is less than about 15 percentof the original total weight of the medium; and b) cumulatively, overall cycles, the change in weight of the medium is no more than about 50percent of the original total weight of the medium, resulting in i) atotal decrease in the COP of said medium of not more than about 5percent; or ii) a loss in electric power generating ability of not morethan about 3 percent.

Preferably, the compounds constituting the aforesaid working medium ofthe invention are CHC1F₂ and one or more compounds of the formula C₂H_(x) X_(y) wherein x and y are integers, y is greater than 1, the sumof x and y is 6, and each X in a given compound can independently be achlorine (Cl) or fluorine (F) radical. The compounds are eithercommercially available or can be readily prepared by methods well-knownin the organic chemistry art. Examples of such compounds are CH₃ CHF₂and CClF₂ CF₃.

In another preferred aspect of the invention, the fluid working mediumcomprises additionally one or more compounds of the type C₄ H₁₀ andCH_(m) Cl_(n) F₃ wherein m and n are integers and m+n=1, i.e., either mor n is 1 and the other is 0. Examples of compounds of the formula C₄H₁₀ are n-butane and iso-butane. Examples of compounds of the formulaCH_(m) Cl_(n) F₃ are chlorotrifluoromethane and trifluoromethane.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the accompanying drawings wherein:

FIG. 1 is a schematic diagram of a refrigeration unit which utilizes thenonazeotropic fluid working medium of the invention.

FIG. 2 is a schematic diagram of an air conditioning device utilizingthe refrigeration unit of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS

The fluid working media of the present invention are useful inthermodynamic compression-condensation-expansion-evaporation cycles, forexample, "heat pump" applications including refrigeration (chilling),air conditioning, heating, and electrical power generating (hot fluid)systems, without the need for expensive modification of existingsystems. The working media comprise at least two fluorocarbons, thetotal mixture being nonazeotropic and having a desirable coefficient ofperformance which is maintained within 95 percent of its original valueafter repeated vaporization loss-replenishment cycles amounting to up to50 percent change in the original weight of the medium, notwithstandingthe changes in the composition of the medium stemming from suchvaporization loss-replenishment cycles, and a loss in hot fluid powergenerating efficiency of not more than about 3 percent.

Referring to the refrigeration unit shown in FIG. 1 of the drawings, thefluid working medium of the invention circulates within the fluidcircuit 15 in the direction of the arrows. The fluid circuit 15interconnects a compressor 20, a condenser 30, a throttle 40 and anevaporator 50. The condenser 30 is connected, via a heat exchanger, to aheat removing means, for example cooling water supply 60. The evaporator50 can be provided in a controlled space for removal of heat from thatspace or may be connected, via a heat exchanger, to a low temperaturefluid circuit 70 in order to provide cooling at a location spaced fromthe evaporator 50.

Referring to FIG. 2 of the drawings, an air-conditioning systemaccording to the present invention includes a refrigerating unit 140 ofthe type shown in FIG. 1 and a fluid circuit 100. The circuit isprovided with fresh air intakes and recirculated air intakes 105 and110, which are mixed in a mixer 120, a fan-and-filter 130, acooling/refrigerating device 140 similar to that shown in FIG. 1, ahumidifier 150, zone heaters 160 connected to fluid dividers 170 and180, each of which feeds zoned compartments 190. Preferred compositionsof the fluid working media of the present invention are illustrated byway of the following non-limiting examples.

EXAMPLE 1

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated from the compound CHC1F₂ and one or more compounds of C₂H_(x) X_(y) wherein x and y are integers, y is greater than 1, the sumof x and y is 6, and each X in a given compound can be independently achlorine (Cl) or fluorine (F) radical.

EXAMPLE 2

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated by admixture of the compound CHClF₂ (R22) and two othercompounds X and Y of the formula C_(n) H_(m) Cl_(x) F_(y) wherein n isan integer, and m, x and y are each independently integers of 0 or more,but m, x and y are not 0 at the same time, each of said two othercompounds X and Y having a normal boiling point within one of thefollowing seven ranges (A-G):

A. -41° C. to -35° C.

B. -35° C. to -20° C.

C. -20° C. to 0° C.

D. 0° C. to 25° C.

E. 25° C. to 35° C.

F. 55° C. to 90° C.

G. 90° C. to 135° C.

Depending on the boiling points of the compounds (R22, X, Y), the weightpercent proportions of the compounds in the medium are as follows:

    ______________________________________                                                     No two Cpds.                                                                             Two Cpds.                                                          in same b.p.                                                                             in same b.p.                                                       range      range                                                 ______________________________________                                        b.p. of X < Y and each is                                                                    R22 > 0.45   R22 > 0.40                                        in range A     0.01 < X < 0.53                                                                            0.01 < X < 0.58                                                  0.01 < Y < 0.53                                                                            0.01 < Y < 0.58                                   b.p. of X < Y and one in                                                                     R22 > 0.46   R22 > 0.41                                        range B        0.01 < X < 0.52                                                                            0.01 < X < 0.57                                                  0.01 < Y < 0.52                                                                            0.01 < Y < 0.57                                   b.p. of X < Y and the b.p.                                                                   R22 > 0.47   R22 > 0.42                                        of X is in range B, the b.p.                                                                 0.01 < X < 0.51                                                                            0.01 < X < 0.56                                   of Y is in range C                                                                           0.01 < Y < 0.51                                                                            0.01 < Y < 0.56                                   b.p. of X is at least in                                                                     R22 > 0.50   R22 > 0.45                                        range B                                                                       b.p. of Y is at least in                                                                     0.01 < X < 0.48                                                                            0.01 < X < 0.53                                   range D        0.01 < Y < 0.48                                                                            0.01 < Y < 0.53                                   ______________________________________                                    

EXAMPLE 3

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated from the compounds CHClF₂ (R22) and three other compoundsX, Y and Z of the formula C_(n) H_(m) Cl_(x) F_(y) wherein n is aninteger, x and y are each independently integers of 0 or more, but m, xand y are not 0 at the same time, each of said three other compounds X,Y and Z having a normal boiling point within one of the following sevenranges (A-G):

A. -41° C. to -35° C.

B. -35° C. to -20° C.

C. -20° C. to 0° C.

D. 0° C. to 25° C.

E. 25° C. to 35° C.

F. 55° C. to 90° C.

G. 90° C. to 135° C.

Accordingly, whether the boiling point of the compounds (R22, X, Y, Z)is in the same range or not, two cases can be created, wherein either notwo of said compounds (R22, X, Y, Z) have normal boiling points withinthe same range or at least two have normal boiling points within thesame range, but the total system does not have a boiling point withinthat range, whereby the concentrations of the compounds in the mediumare as follows:

    ______________________________________                                                     No two Cpds.                                                                             Two Cpds in                                                        in same b.p. range                                                                       same b.p. range                                       ______________________________________                                        b.p. of X < Y < Z and                                                                        R22 > 0.35   R22 > 0.32                                        each is in range A                                                                           0.01 < X < 0.60                                                                            0.01 < X < 0.63                                                  0.01 < Y < 0.60                                                                            0.01 < Y < 0.63                                                  0.01 < Z < 0.60                                                                            0.01 < Z < 0.63                                   b.p. of X < Y < Z and                                                                        R22 > 0. 36  R22 > 0.33                                        each is in range B                                                                           0.01 < X < 0.59                                                                            0.01 < X < 0.62                                                  0.01 < Y < 0.59                                                                            0.01 < Y < 0.62                                                  0.01 < Z < 0.59                                                                            0.01 < Z < 0.62                                   b.p. of X < Y < Z and                                                                        R22 > 0.37   R22 > 0.34                                        each is in range B or at                                                                     0.01 < X < 0.58                                                                            0.01 < X < 0.61                                   least one is in range C                                                                      0.01 < Y < 0.58                                                                            0.01 < Y < 0.61                                                  0.01 < Z < 0.58                                                                            0.01 < Z < 0.61                                   b.p. of X < Y < Z, and                                                                       R22 > 0.40   R22 > 0.37                                        b.p.'s of X and Y are at                                                                     0.01 < X < 0.55                                                                            0.01 < X < 0.58                                   least in range B, and b.p.                                                                   0.01 < Y < 0.55                                                                            0.01 < Y < 0.58                                   of Z is at least in range D                                                                  0.01 < Z < 0.55                                                                            0.01 < Z < 0.58                                   ______________________________________                                    

EXAMPLE 4

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated from the compounds CHClF₂ (R22) and four other compoundsU, X, Y and Z of the formula C_(n) H_(m) Cl_(x) F_(y) wherein n is aninteger, m, x and y are each independently integers of 0 or more, but m,x and y are not 0 at the same time, each of said four other compounds U,X, Y and Z having a normal boiling point within one of the followingseven ranges (A-G):

A. -41° to -35° C.

B. -35° to -20° C.

C. -20° to 0° C.

D. 0° to 25° C.

E. 25° to 35° C.

F. 55° to 90° C.

G. 90° to 135° C.

Accordingly, whether the boiling point of the compounds (R22, U, X, Y,Z) is in the same range or not, two cases can be created, wherein eitherno two of said compounds (R22, U, X, Y, Z) have normal boiling pointswithin in the same range or at least two have normal boiling pointswithin the same range, but the total system does not have a boilingpoint within that range, whereby the concentrations of the compounds inthe medium are as follows:

    ______________________________________                                                     No two Cpds. in                                                                          Two Cpds. in                                                       same b.p. range                                                                          same b.p. range                                       ______________________________________                                        b.p. of U < X < Y < Z                                                                        R22 > 0.33   R22 > 0.3                                         and each is in range A                                                                       0.01 < U < 0.62                                                                            0.01 < U < 0.65                                                  0.01 < X < 0.62                                                                            0.01 < X < 0.65                                                  0.01 < Y < 0.62                                                                            0.01 < Y < 0.65                                                  0.01 < Z < 0.62                                                                            0.01 < Z < 0.65                                   b.p. of U < X < Y < Z                                                                        R22 > 0.34   R22 > 0.31                                        and each is in range B                                                                       0.01 < U < 0.61                                                                            0.01 < U < 0.64                                                  0.01 < X < 0.61                                                                            0.01 < X < 0.64                                                  0.01 < Y < 0.61                                                                            0.01 < Y < 0.64                                                  0.01 < Z < 0.61                                                                            0.01 < Z < 0.64                                   b.p. of U < X < Y < Z                                                                        R22 > 0.35   R22 > 0.32                                        and each is in range B or                                                                    0.01 < U < 0.60                                                                            0.01 < U < 0.63                                   at least one is in range C                                                                   0.01 < X < 0.60                                                                            0.01 < X < 0.63                                                  0.01 < Y < 0.60                                                                            0.01 < y < 0.63                                                  0.01 < Z < 0.60                                                                            0.01 < Z < 0.63                                   b.p. of U < X < Y < Z,                                                                       R22 > 0.38   R22 > 0.35                                        and b.p. of U, X and Y are                                                                   0.01 < U < 0.57                                                                            0.01 < U < 0.60                                   at least in range B, and                                                                     0.01 < X < 0.57                                                                            0.01 < X < 0.60                                   b.p. of Z is at least in                                                                     0.01 < Y < 0.57                                                                            0.01 < Y < 0.60                                   range D        0.01 < Z < 0.57                                                                            0.01 < Z < 0.60                                   ______________________________________                                    

Example 5

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated from the compounds CHClF₂ (R22) and four or more othercompounds X1, X2, X3, . . . , Xn of the formula C_(n) H_(m) Cl_(x) F_(y)wherein n is the integer, m, x, and y are each independently integers of0 or more, but m, x and y are not 0 at the same time, each of said fouror more other compounds X1, X2, X3, . . . , Xn having a normal boilingpoint within one of the following seven ranges (A-G):

A. -41° C. to -35° C.

B. -35° C. to -20° C.

C. -20° C. to 0° C.

D. 0° C. to 25° C.

E. 25° C. to 35° C.

F. 55° C. to 90° C.

G. 90° C. to 135° C.

Accordingly, whether the boiling point of the compounds (R22, X1, X2,X3,. . . , Xn) is in the same range or not, two cases can be created,wherein either no two of said compounds (R22, X1, X2, X3, , . . . , Xn)have normal boiling points with the same range or at least two havenormal boiling points within the same range, but the total system doesnot have a boiling point within that range, whereby the concentrationsof the compounds in the medium are as follows:

    __________________________________________________________________________                   No two Cpds. in same b.p.                                                                    Two Cpds. in same b.p.                                         range          range                                           __________________________________________________________________________    b.p. of        R22 > 0.33     R22 > 0.30                                      X1 < X2 < X3 < . . . < Xn                                                                    0.01 < X1 < (0.67-N × 0.01)                                                            0.01 < X1 < (0.70-N × 0.01)               and each is in range A                                                                       0.01 < X2 < (0.67-N × 0.01)                                                            0.01 < X2 < (0.70-N × 0.0 1)                             0.01 < X3 < (0.67-N × 0.01)                                                            0.01 < X3 < (0.70-N × 0.01)                              0.01 < Xn < (0.67-N × 0.01)                                                            0.01 < Xn < (0.70-N × 0.01)               b.p. of        R22 > 0.34     R22 > 0.31                                      X1 < X2 < X3 < . . . < Xn                                                                    0.01 < X1 < (0.66-N × 0.01)                                                            0.01 < X1 < (0.69-N × 0.01)               and each is in range B                                                                       0.01 < X2 < (0.66-N × 0.01)                                                            0.01 < X2 < (0.69-N × 0.01)                              0.01 < X3 < (0.66-N × 0.01)                                                            0.01 < X3 < (0.69-N × 0.01)                              0.01 < Xn < (0.66-N × 0.01)                                                            0.01 < Xn < (0.69-N × 0.01)               b.p. of        R22 > 0.35     R22 > 0.32                                      X1 < X2 < X3 < . . . < Xn,                                                                   0.01 < X1 < (0.65-N × 0.01)                                                            0.01 < X1 < (0.68-N × 0.01)               with at least one in                                                                         0.01 < X2 < (0.65-N × 0.01)                                                            0.01 < X2 < (0.68-N × 0.01)               range C and the others                                                                       0.01 < X3 < (0.65-N × 0.01)                                                            0.01 < X3 < (0.68-N × 0.01)               in range B     0.01 < Xn < (0.65-N × 0.01)                                                            0.01 < Xn < (0.68-N × 0.01)               b.p. of        R22 > 0.38     R22 > 0.35                                      X1 < X2 < X3 < . . . < Xn,                                                                   0.01 < X1 < (0.62-N × 0.01)                                                            0.01 < X1 < (0.65-N × 0.01)               and b.p.'s of  0.01 < X2 < (0.62-N × 0.01)                                                            0.01 < X2 < (0.65-N × 0.01)               X1, X2, X3, . . . ,                                                                          0.01 < X3 < (0.62-N × 0.01)                                                            0.01 < X3 < (0.65-N × 0.01)               X1(3 < i < n) are at least                                                                   0.01 < Xn < (0.62-N × 0.01)                                                            0.01 < Xn < (0.65-N × 0.01)               in range B and the                                                            b.p.'s of X(i + 1), . . . ,Xn                                                 are at least in range D                                                       __________________________________________________________________________

EXAMPLE 6

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated from three compounds P, X and Y of the formula C_(n) H_(m)Cl_(x) F_(y) wherein n is an integer, and m, x and y are eachindependently integers of 0 or more, but m, x and y are not 0 at thesame time. The boiling point of P is the lowest, with each of theremaining compounds X and Y having a normal boiling point within one ofthe following seven ranges (A-G):

A. -45° to -35° C.

B. -35° to -20° C.

C. -20° to 0° C.

D. 0° to 25° C.

E. 25° to 35° C.

F. 55° to 90° C.

G. 90° to 135° C.

Accordingly, whether the boiling point of the compounds (P, X, Y) in thesame range or not, two cases can be created, wherein either no two ofsaid compounds (P, X, Y) have normal boiling points within the samerange or at least two have normal boiling points within the same range,but the total system does not have a boiling point within that range,whereby the concentrations of the compounds in the medium are asfollows:

    ______________________________________                                                     No two Cpds. in                                                                          Two Cpds. in                                                       same b.p. range                                                                          same b.p. range                                       ______________________________________                                        b.p. of X < Y each is in                                                                     P < 0.45     P < 0.40                                          range A        0.01 < X < 0.53                                                                            0.01 < X < 0.58                                                  0.01 < Y < 0.53                                                                            0.01 < Y < 0.58                                   b.p. of X < Y each is in                                                                     P < 0.46     P < 0.40                                          range B        0.01 < X < 0.52                                                                            0.01 < X < 0.57                                                  0.01 < Y < 0.52                                                                            0.01 < Y < 0.57                                   b.p. of X < Y and b.p. of                                                                    P < 0.47     P < 0.40                                          X is in range B, and b.p. of                                                                 0.01 < X < 0.51                                                                            0.01 < X < 0.56                                   Y is in range C                                                                              0.01 < Y < 0.51                                                                            0.01 < Y < 0.56                                   b.p. of X is at least in                                                                     P < 0.50     P < 0.45                                          range B and b.p. of Y is at                                                                  0.01 < X < 0.48                                                                            0.01 < X < 0.53                                   least in range D                                                                             0.01 < Y < 0.48                                                                            0.01 < Y < 0.53                                   ______________________________________                                    

EXAMPLE 7

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated from four compounds P, X, Y and Z and the formula C_(n)H_(m) Cl_(x) F_(y) wherein n is an integer, x and y are eachindependently integers of 0 or more, but m, x and y are not 0 at thesame time. The boiling point of P is the lowest, with each of theremaining compounds X, Y and Z having a normal boiling point within oneof the following seven ranges (A-G):

A. -45° to -35° C.

B. -35° to -20° C.

C. -20° to 0° C.

D. 0° to 25° C.

E. 25° to 35° C.

F. 55° to 90° C.

G. 90° to 135° C.

Accordingly, whether the boiling point of the compounds (P, X, Y, Z) isin the same range or not, two cases can be created, wherein either notwo of said compounds (P, X, Y, Z) have normal boiling points within thesame range or at least two have normal boiling points within the samerange, but the total system does not have a boiling point within thatrange, whereby the concentrations of the compounds in the medium are asfollows:

    ______________________________________                                                     No two Cpds. in                                                                          Two Cpds. in                                                       same b.p. range                                                                          same b.p. range                                       ______________________________________                                        b.p. of X < Y < Z and                                                                        P > 0.35     P > 0.32                                          each is in range A                                                                           0.01 < X < 0.60                                                                            0.01 < X < 0.63                                                  0.01 < Y < 0.60                                                                            0.01 < Y < 0.63                                                  0.01 < Z < 0.60                                                                            0.01 < Z < 0.63                                   b.p. of X < Y < Z and                                                                        P > 0.36     P > 0.33                                          each is in range B                                                                           0.01 < X < 0.59                                                                            0.01 < X < 0.62                                                  0.01 < Y < 0.59                                                                            0.01 < Y < 0.62                                                  0.01 < Z < 0.59                                                                            0.01 < Z < 0.62                                   b.p. of X < Y < Z and                                                                        P > 0.37     P > 0.34                                          b.p.'s are in range B or at                                                                  0.01 < X < 0.58                                                                            0,01 < X < 0.61                                   least one is in range C                                                                      0.01 < Y < 0.58                                                                            0.01 < Y < 0.61                                                  0.01 < Z < 0.58                                                                            0.01 < Z < 0.61                                   b.p. of X < Y < Z,                                                                           P > 0.40     P > 0.37                                          and b.p.'s of X and Y are                                                                    0.01 < X < 0.55                                                                            0.01 < X < 0.58                                   at least in range B, and                                                                     0.01 < Y < 0.55                                                                            0.01 < Y < 0.58                                   b.p. of Z is at least in                                                                     0.01 < Z < 0.55                                                                            0.01 < Z < 0.58                                   range D                                                                       ______________________________________                                    

EXAMPLE 8

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated from the compounds P, U, X, Y and Z of the formula C_(n)H_(m) Cl_(x) F_(y) wherein n is an integer, m, x and y are eachindependently integers of 0 or more, but m, x and y are not 0 at thesame time. The boiling point of P is the lowest, with each of theremaining of the compounds U, X, Y and Z having a normal boiling pointwithin one of the following seven ranges (A-G):

A. -45° to -35° C.

B. -35° to -20° C.

C. -20° to 0° C.

D. 0° to 25° C.

E. 25° to 35° C.

F. 55° to 90° C.

G. 90° to 135° C.

Accordingly, whether the boiling point of the compounds (P, U, X, Y, Z)is in the same range or not, two cases can be created, wherein either notwo of said compounds (P, U, X, Y, Z) have normal boiling points withinthe same range or at least two have normal boiling points within thesame range, but the total system does not have a boiling point withinthat range, whereby the concentrations of the compounds in the mediumare as follows:

    ______________________________________                                                     No two Cpds. in                                                                          Two Cpds. in                                                       same b.p. range                                                                          same b.p. range                                       ______________________________________                                        b.p. of U < X < Y < Z                                                                        P > 0.33     P > 0.30                                          and each is in range A                                                                       0.01 < U < 0.62                                                                            0.01 < U < 0.65                                                  0.01 < X < 0.62                                                                            0.01 < X < 0.65                                                  0.01 < Y < 0.62                                                                            0.01 < Y < 0.65                                                  0.01 < Z < 0.62                                                                            0.01 < Z < 0.65                                   b.p. of U < X < Y < Z                                                                        P > 0.34     P > 0.31                                          and each is in range B                                                                       0.01 < U < 0.61                                                                            0.01 < U < 0.64                                                  0.01 < X < 0.61                                                                            0.01 < X < 0.64                                                  0.01 < Y < 0.61                                                                            0.01 < Y < 0.64                                                  0.01 < Z < 0.61                                                                            0.01 < Z < 0.64                                   b.p. of U < X < Y < Z                                                                        P > 0.35     P > 0.32                                          and b.p.'s are in range B                                                                    0.01 < U < 0.60                                                                            0.01 < U < 0.63                                   or at least one is in range                                                                  0.01 < X < 0.60                                                                            0.01 < X < 0.63                                   C              0.01 < Y < 0.60                                                                            0.01 < Y < 0.63                                                  0.01 < Z < 0.60                                                                            0.01 < Z < 0.63                                   b.p. of U < X < Y < Z,                                                                       P > 0.38     P > 0.35                                          and b.p.'s of U, X and Y                                                                     0.01 < U < 0.57                                                                            0.01 < U < 0.60                                   are at least in range B, and                                                                 0.01 < X < 0.57                                                                            0.01 < X < 0.60                                   b.p. of Z is at least in                                                                     0.01 < Y < 0.57                                                                            0.01 < Y < 0.60                                   range D        0.01 < Z < 0.57                                                                            0.01 < Z < 0.60                                   ______________________________________                                    

EXAMPLE 9

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated from the compounds P, X1, X2, X3, . . . , Xn of theformula C_(n) H_(m) Cl_(x) F_(y) wherein n is the integer, m, x, and yare each independently integers of 0 or more, but m, x and y are not 0at the same time. The boiling point of P is the lowest, with each of theremaining compounds X1, X2, X3, . . . , Xn having a normal boiling pointwithin one of the following seven ranges (A-G):

A. -45° C. to -35° C.

B. -35° C. to -20° C.

C. -20° C. to 0° C.

D. 0° C. to 25° C.

E. 25° C. to 35° C.

F. 55° C. to 90° C.

G. 90° C. to 135° C.

Accordingly, whether the boiling point of the compounds (P, X1, X2, X3,. . . , Xn) is in the same range or not, two cases can be created,wherein either no two of said compounds (P, X1, X2, X3, . . . Xn) havenormal boiling points within the same range or at least two have normalboiling points within the same range, but the total system does not havea boiling point within that range, whereby the concentrations of thecompounds in the medium are as follows:

    __________________________________________________________________________                   No two Cpds. in same b.p.                                                                    Two Cpds. in same b.p.                                         range          range                                           __________________________________________________________________________    b.p. of        P > 0.33       P > 0.30                                        X1 < X2 < X3 < . . . < Xn                                                                    0.01 < X1 < (0.67-N × 0.01)                                                            0.01 < X1 < (0.70-N × 0.01)               and each is in range A                                                                       0.01 < X2 < (0.67-N × 0.01)                                                            0.01 < X2 < (0.70-N × 0.01)                              0.01 < X3 < (0.67-N × 0.01)                                                            0.01 < X3 < (0.70-N × 0.01)                              0.01 < xn < (0.67-N × 0.01)                                                            0.01 < Xn < (0.70-N × 0.01)               b.p. of        P > 0.34       P > 0.31                                        X1 < X2 < X3 < . . . < Xn                                                                    0.01 < X1 < (0.66-N × 0.01)                                                            0.01 < X1 < (0.69-N × 0.01)               and each is in range B                                                                       0.01 < X2 < (0.66-N × 0.01)                                                            0.01 < X2 < (0.69-N × 0.01)                              0.01 < X3 < (0.66-N × 0.01)                                                            0.01 < X3 < (0.69-N × 0.01)                              0.01 < Xn < (0.66-N × 0.01)                                                            0.01 < Xn < (0.69-N × 0.01)               b.p. of        P > 0.35       P > 0.32                                        X1 < X2 < X3 < . . . < Xn,                                                                   0.01 < X1 < (0.65-N × 0.01)                                                            0.01 < X1 < (0.68-N × 0.01)               with at least one in                                                                         0.01 < X2 < (0.65-N × 0.01)                                                            0.01 < X2 < (0.68-N × 0.01)               range C and the others                                                                       0.01 < X3 < (0.65-N × 0.01)                                                            0.01 < X3 < (0.68-N × 0.01)               in range B     0.01 < Xn < (0.65-N × 0.01)                                                            0.01 < Xn < (0.68-N × 0.01)               b.p. of        P > 0.38       P > 0.35                                        X1 < X2 < X3 < . . . < Xn                                                                    0.01 < X1 < (0.62-N × 0.01)                                                            0.01 < X1 < (0.65-N × 0.01)               and the b.p.'s of                                                                            0.01 < X2 < (0.62-N × 0.01)                                                            0.01 < X2 < (0.65-N × 0.01)               X1, X2, X3, . . . ,                                                                          0.01 < X3 < (0.62-N × 0.01)                                                            0.01 < X3 < (0.65-N × 0.01)               X1(3 < i < n) are at least                                                                   0.01 < Xn < (0.62-N × 0.01)                                                            0.01 < Xn < (0.65-N × 0.01)               in range B and the                                                            b.p.'s of X(i + 1), . . . , Xn                                                are at least in range D                                                       __________________________________________________________________________

EXAMPLE 10

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated to comprise the following compounds in the weightconcentrations as follows:

    ______________________________________                                        CCl.sub.2 F.sub.2 (R12)                                                                        0.02-0.25                                                    CHClF.sub.2 (R22)                                                                              0.5-0.7                                                      CClF.sub.2 CF.sub.3 (R115)                                                                      0.1-0.45                                                    ______________________________________                                    

When each of said compounds is in the following weight concentration,the working fluid medium has the best vaporization loss stability:

    ______________________________________                                        CCl.sub.2 F.sub.2 (R12)                                                                         0.14                                                        CHClF.sub.2 (R22) 0.59                                                        CClF.sub.2 CF.sub.3 (R115)                                                                      0.27                                                        ______________________________________                                    

When said compounds contain less than 10 percent (by weight) ofimpurity, the effect on the thermophysical property of the working fluidmedium can be negligible.

EXAMPLE 11

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated to comprise the following compounds in the weightconcentration as follows:

    ______________________________________                                        CH(CH.sub.3).sub.3 (R600a)                                                                     0.02-0.2                                                     CHClF.sub.2 (R22)                                                                              0.5-0.7                                                      CH.sub.3 CHF.sub.2 (R152a)                                                                      0.1-0.45                                                    ______________________________________                                    

When each of said compounds is in the following weight concentration,the working fluid medium has the best vaporization loss stability:

    ______________________________________                                        CH(CH.sub.3).sub.3 (R600a)                                                                      0.09                                                        CHClF.sub.2 (R22) 0.62                                                        CH.sub.3 CHF.sub.2 (R152a)                                                                      0.29                                                        ______________________________________                                    

When said compounds contain less than 10 percent (by weight) ofimpurity, the effect on the thermophysical property of the working fluidmedium can be negligible.

EXAMPLE 12

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated to comprise the following compounds in the weightconcentrations as follows:

    ______________________________________                                        CH.sub.3 (CH.sub.2).sub.2 CH.sub.3 (R600)                                                        0.02-0.2                                                   CHClF.sub.2 (R22)  0.5-0.7                                                    CH.sub.3 CHF.sub.2 (R152a)                                                                       0.1-0.45                                                   ______________________________________                                    

When each of said compounds is in the following weight concentration,the working fluid medium has the best vaporization loss stability:

    ______________________________________                                        CH.sub.3 (CH.sub.2).sub.2 CH.sub.3 (R600)                                                        0.06                                                       CHClF.sub.2 (R22)  0.63                                                       CH.sub.3 CHF.sub.2 (R152a)                                                                       0.31                                                       ______________________________________                                    

When said compounds contain less than 10 percent (by weigh) of impurity,the effect on the thermophysical property of the working fluid mediumcan be negligible.

EXAMPLE 13

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated to comprise the following compounds in the weightconcentrations as follows:

    ______________________________________                                        CCl.sub.2 F.sub.2 (R12)                                                                        0.75-0.9                                                     CH.sub.3 CHF.sub.2 (R152a)                                                                     0.02-0.2                                                     CH(CH.sub.3).sub.3 (R600a)                                                                      0.0-0.11                                                    CF.sub.3 CH.sub.2 F (R134a)                                                                     0.0-0.15                                                    ______________________________________                                    

When each of said compounds is in the following weight concentration,the working fluid medium has the best vaporization loss stability:

    ______________________________________                                        CCl.sub.2 F.sub.2 (R12)                                                                         0.82                                                        CH.sub.3 CHF.sub.2 (R152a)                                                                      0.1                                                         CH(CH.sub.3).sub.3 (R600a)                                                                      0.03                                                        CF.sub.3 CH.sub.2 F (R134a)                                                                     0.05                                                        ______________________________________                                    

When said compounds contain less than 10 percent (by weigh) of impurity,the effect on the thermophysical property of the working fluid mediumcan be negligible.

EXAMPLE 14

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated to comprise the following compounds in the weightconcentrations:

    ______________________________________                                        CHClF.sub.2 (R22)                                                                              0.35-0.55                                                    CH.sub.3 CHF.sub.2 (R152a)                                                                     0.05-0.30                                                    CF.sub.3 CH.sub.2 F (R134a)                                                                    0.05-0.30                                                    CF.sub.3 F.sub.8 (RC318)                                                                       0.05-0.30                                                    ______________________________________                                    

When each of said compounds is in the following weight concentration,the working fluid medium has the best vaporization loss stability:

    ______________________________________                                        CHClF.sub.2 (R22) 0.45                                                        CH.sub.3 CHF.sub.2 (R152a)                                                                      0.15                                                        CF.sub.3 CH.sub.2 F (R134a)                                                                     0.27                                                        C.sub.4 F.sub.8 (RC318)                                                                         0.13                                                        ______________________________________                                    

When said compounds contain less than 10 percent (by weigh) of impurity,the effect on the thermophysical property of the working fluid mediumcan be negligible.

EXAMPLE 15

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated to comprise the following compounds in the weightconcentrations:

    ______________________________________                                        CHClF.sub.2 (R22)                                                                              0.4-0.75                                                     CH.sub.3 CHF.sub.2 (R152a)                                                                     0.0-0.2                                                      CF.sub.3 CH.sub.2 F (R134a)                                                                    0.0-0.25                                                     C.sub.3 H.sub.9 (R290)                                                                         0.05-0.25                                                    ______________________________________                                    

When each of said compounds is in the following weight concentration,the working fluid medium has the best vaporization loss stability:

    ______________________________________                                        CHClF.sub.2 (R22) 0.71                                                        CH.sub.3 CHF.sub.2 (R152a)                                                                      0.05                                                        CF.sub.3 CH.sub.2 F (R134a)                                                                     0.09                                                        C.sub.3 H.sub.8 (R290)                                                                          0.15                                                        ______________________________________                                    

When said compounds contain less than 10 percent (by weigh) of impurity,the effect on the thermophysical property of the working fluid mediumcan be negligible.

EXAMPLE 16

A nonazeotropic working fluid medium having the vaporization lossstability is formulated to comprise the following compounds in theweight concentrations:

    ______________________________________                                        CHClF.sub.2 (R22)                                                                              0.48-0.75                                                    CH.sub.3 CHF.sub.2 (R152a)                                                                     0.05-0.35                                                    C.sub.4 F.sub.8 (RC318)                                                                        0.05-0.35                                                    ______________________________________                                    

When each of said compounds is in the following weight concentration,the working fluid medium has the best vaporization loss stability:

    ______________________________________                                        CHClF.sub.2 (R22) 0.70                                                        CH.sub.3 CHF.sub.2 (R152a)                                                                      0.18                                                        C.sub.4 F.sub.8 (RC318)                                                                         0.12                                                        ______________________________________                                    

When said compounds contain less than 10 percent (by weigh) of impurity,the effect on the thermophysical property of the working fluid mediumcan be negligible.

EXAMPLE 17

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated to comprise the following compounds in the weightconcentrations:

    ______________________________________                                        CHClF.sub.2 (R22)                                                                              0.35-0.80                                                    CH.sub.3 CHF.sub.2 (R152a)                                                                     0.02-0.30                                                    CH.sub.3 CClF.sub.2 (R1426)                                                                    0.01-0.25                                                    C.sub.4 F.sub.8 (RC3 18)                                                                       0.03-0.55                                                    ______________________________________                                    

When each of said compounds is in the following weight concentration,the working fluid medium has the best vaporization loss stability:

    ______________________________________                                        CHClF.sub.2 (R22) 0.41                                                        CH.sub.3 CHF.sub.2 (R152a)                                                                      0.13                                                        CH.sub.3 CClF.sub.2 (R142b)                                                                     0.12                                                        C.sub.4 F.sub.8 (RC318)                                                                         0.34                                                        ______________________________________                                    

EXAMPLE 18

A nonazeotropic working fluid medium having vaporization loss stabilityformulated to comprise the following compounds in the weightconcentrations:

    ______________________________________                                        CHClF.sub.2 (R22)  0.5-0.96                                                   CH.sub.3 CHCH.sub.2 (R1270)                                                                     0.005-0.1                                                   CH.sub.3 CHF.sub.2 (R152a)                                                                      0.01-0.25                                                   ______________________________________                                    

When said compounds contain less than 10 percent (by weigh) of impurity,the effect on the thermophysical property of the working fluid mediumcan be negligible.

EXAMPLE 19

A nonazeotropic working fluid medium having vaporization loss stabilityis formulated to comprise the following compounds in the weightconcentrations:

    ______________________________________                                        CHClF.sub.2 (R22)  0.89                                                       CH.sub.3 CHCH.sub.2 (R1270)                                                                      0.03                                                       CH.sub.3 CHF.sub.2 (R152a)                                                                       0.08                                                       ______________________________________                                    

When said compounds contain less than 10 percent (by weigh) of impurity,the effect on the thermophysical property of the working fluid mediumcan be negligible.

The non-azeotropic fluid working medium, apparatus and method disclosedhereinabove are intended to be descriptive, rather than limitative ofthe scope of the present invention as defined in the following claims.

What is claimed is:
 1. A nonazeotropic working fluid medium for use in athermodynamic cycle system, comprising a mixture of compounds andcharacterized in that, when subject to one or more vaporizationloss/replenishment cycles:(a) the weight of the medium changes is lessthan about 15% of the total original weight of the medium per cycle,wherein the compounds and their weight concentrations are as follows:

    ______________________________________                                        CHClF.sub.2 (R22)                                                                              0.35-0.80                                                    CH.sub.3 CHF.sub.2 (R152a)                                                                     0.02-0.30                                                    CH.sub.3 CClF.sub.2 (R142b)                                                                    0.01-0.25                                                    C.sub.4 F.sub.8 (RC318)                                                                         0.03-0.55,                                                  ______________________________________                                    

and wherein the maximum concentration of impurities in the medium isabout 10 percent by weight; and (b) cumulatively, over all cycles, theweight of the medium changes is no more than about 50% of the totaloriginal weight of the medium, resulting in:i) a total decrease in thecoefficient of performance of said medium of no more than about 5%; orii) a loss in electric power generating efficiency of not more thanabout 3 percent.
 2. A nonazeotropic working fluid medium according toclaim 1, wherein the compounds and their weight concentrations are asfollows:

    ______________________________________                                        CHClF.sub.2 (R22) 0.41                                                        CH.sub.3 CHF.sub.2 (R152a)                                                                      0.13                                                        CH.sub.3 CClF.sub.2 (R142b)                                                                     0.12                                                        C.sub.4 F.sub.8 (RC318)                                                                          0.34.                                                      ______________________________________                                    